Abstract:
Steering feel and quality are terms commonly used in the automotive industry when
describing passenger car steering systems. However, a procedure for the quantification
of these terms does not exist, let alone a concise definition of what they constitute.
This thesis puts forward a hypothesis by which steering quality and feel are described
by the input/output relationships of the steering system and how they are perceived
by the driver. Good control properties are postulated for these relationships and an
experiment is conducted, where they are altered in a manner proposed to affect quality.
A methodology for the objective assessment of the control properties is developed,
employing vehicle dynamic testing and representation by a mathematical model. This
is put into practice to evaluate the outcome of the experiment.
It was found that the methodology was successful in detecting and quantifying the
alteration in the vehicle control properties. A subjective evaluation was performed to
assess the experiment in terms of the quality and feel perceived by the driver. The
subjective judgement delivered a result, where the deviation in quality agreed with
the objective quantities hypothesised to describe quality.
The thesis provides a significant step in the understanding of what is termed steering
feel and quality. The methodology, successful in quantifying the experimental results
with respect to quality, constitutes a scientific advancement in the current procedures
for the assessment of steering quality.
